If its Warming, Why Is Winter So Darn Cold?

This is a common global warming question, especially from those of us living at or above the 45th parallel. In North America, this covers Minnesota, North Dakota, Maine, Montana, and north into Canada. Oregon and Washington, in the same latitude, escape only because of their westerly location near the Pacific.

Last winter was cold. This winter is expected to be equally as cold. It’s hard to believe in global warming when toes turn blue inside the house after the first hard frost. For those of us in this frozen wasteland, a decade of warm winters followed by one – and potentially two – hard winters makes global warming seem like another ripoff from which we will never benefit, and we would cheerfully blame Wall Street if we could find a way.

The answer, however, is complex – perhaps even incalculable. A lot of the earth’s temperature depends on ocean currents (the Pacific Decadal Oscillation, El Nino, La Nina) and the global winds that derive their temperature from these currents. It also depends, in part, on factors we don’t have the historical experience to calculate, like sun activity (or its lack). It may even depend on factors we’re not fully aware or cognizant of, like the density or rotation of the of the earth’s magnetic core.

The theory of global warming is now accepted fact among most reputable scientists, and climate scientist Michael Mann’s famed “hockey stick” graph of this warming (formulated in 1998, repudiated in 2001-2005, and finally supported by additional science this year) shows anthropogenic causes as the culprit. In short, our increasing use of fossil fuels since the mid 1800s has caused the planet to warm.

Arguments aside (global warming is a myth designed to sell carbon credits; global warming is the result of the sun’s inactivity; global warming is a natural rise in temperature marking the end of the last Little Ice Age), the fact remains that the earth iswarmer now than during the past 100 years, and the only identifiable, documented and recognizable cause appears to be man.

The fact that Mars is emerging from its own little ice age is, arguably, peripheral, as is the fact that inactive sun cycles (which occur in approximately 11-year intervals) have caused marginal cooling in other times. The reason the sun can’t be held to blame is that solar radiation has remained more or less constant from 1950 to the present, yet temperatures continue to climb.

Or so some scientists claim. Others argue that temperatures are actually cooling, the datasets are all wrong, and we’re heading into an ice age. Proving yet again that if you torture the data long enough, it will confess to anything, so let’s stick to warming as the logical consequence.

Global warming scientists brush away last year’s surprisingly cold winter by explaining that not all areas on earth will warm at the same rate. Some areas may in fact become cooler, at least during the first few decades of this century. This is the result of those previously mentioned ocean currents, which scientists at the International Council for the Exploration of the Seas (ICES) explain are cooling thanks to Arctic ice melting.

The ICES, an intergovernmental organization that promotes marine research in the North Atlantic, recently met in Halifax, Nova Scotia (eastern Canada) and warned that global warming may actually mean colder weather for the Atlantic seaboard, including Atlantic Canada, if melting Arctic ice keeps pace with its 2007 record (a compilation achieved via satellite photos since 1979).

How does melting Arctic ice influence the temperature? Simply explained, the melting ice creates a cooler surface layer on the ocean. This layer doesn’t immediately sink, even though cold water is denser (heavier) than hot, because fresh water is lighter than salt water. This, in effect, alters the meridional overturning circulation, where warm ocean currents move north and colder currents move south to equalize their temperatures. Failure of the meridional circulation is predicted to mean a harsher and possibly colder climate for Atlantic regions and even Great Britain. No one knows for certain, and scientists are more openly hesitant to predict the consequences of this factor than any other attributed to global temperature fluctuations, even including the current absence of sunspots.

So what can we expect if cooler ocean temperatures, and not a lazy sun, are reducing the regional impacts of global warming? Northern climates, particularly those in the Atlantic region, should become shorter but colder in winter and more temperate, though drier, in summer. It will be easier to grow some kinds of fruit trees from Maine to Minnesota (with appropriate winter wrapping), but tornadoes may be intensified. Cities will be spared for the most part, if only because their physical footprint is much smaller than their carbon footprint. Rain, when it falls, will likely be torrential, leading to more flooding. Frost will come later, and lighter, but drier conditions will necessitate watering gardens and irrigating croplands – a real problem as increasingly depleted water reserves (lakes and streams) become a hot-button issue.

The Great Lakes area is likely to suffer the least in terms of water, thanks to the newly passed Great Lakes Compact, which needs only signing to become law. This Compact effectively limits water from the Great Lakes area (Lakes Superior, Huron, Michigan, Erie and Ontario) to regional users, and prevents its sale to outside entities unless approved by all signatories of the Compact, including Canadian provinces bordering the Lakes.

Global warming in the future will mean different things to people in different locations. North of 45 degrees latitude, it might be wise to invest in alternative heating solutions – preferably renewable – hip waders, storm cellars and a few grape vines for those shorter but somewhat colder winters. The upside is, the mosquito population won’t be nearly as bad.